eli5: How will we produce plastics after oil is depleted?

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As far I know we can get Etilene from Alcohol which can be polymerized into Polyetilene and later you can get PVC if you get vinyl chloride from PE. Is there a way to get other plastics apart from oil byproducts?

In: Chemistry

4 Answers

Anonymous 0 Comments

Oil is just carbon and hydrogen bound together (plus stuff that you don’t want anyway). You can produce it artificially from everything else that contains carbon – plants, or even carbon dioxide from the air. Hydrogen is either part of the stuff already or can be extracted from water. You need energy to do so and it’s much more expensive than pumping it out of the ground, so currently no one does it outside of a lab. But it’s possible.

Anonymous 0 Comments

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Anonymous 0 Comments

You can always build them up from scratch; with enough energy you can just get hydrogen from water and carbon from pretty much anywhere and synthesize whatever you want.

This isn’t energy efficient *at all* but, if we’re out of oil, then we’ve either sorted out alternative energy sources and have a lot of renewable power available or lack of plastic is the least of our problems.

There are lots of interim options though…organic chemists are very clever. As long as you have some kind of hydrocarbon feedstock (and tons of plants make those) you can eventually get to almost anything you want.

Edit:typo

Anonymous 0 Comments

Oil (and gas) depletion is theoretical. If (this is within any forecastable period – ie not 2 centuries from now) oil production depletes, prices will rise dramatically. This will make oil financially infeasible as an energy source long before actual physical depletion.

Road transportation accounts for 2/3rds (approx) of oil use with around 2/3rds (approx) used for cars/motor vehicles. It is likely that most of that goes away. Jet fuel accounts for another 12% and this would likely reduce significantly once price increases.

Although it isn’t as cheap (today), it is also possible to make hydrocarbon feedstock from things like coal (which is far more abundant) or biomass (mostly renewable).

Far more of a problem is that gas prices would also rise significantly along with oil. Gas is not only used for energy but a lot of it is used to make fertilizer. Running out of cheap fertilizer means global food insecurity rises exponentially. Rich countries can probably afford it (although with far higher food costs) but poorer countries and countries with poor soil would starve.

Brazil, India, China, Indonesia (and a big bunch of other smaller countries) might have a huge problem because they use 2x to 3x the amount of fertilizer per acre of arable land compared to countries that have better soil. These four countries alone account for over 40% of the world’s population.

In short, plastics manufacturing would be the least of the problems should we run out of cheap oil.